Tapered rollers are used for a wide variety of purposes. Simply by way of example, conveyor systems for moving finished and unfinished products to various locations in facilities such as factories and distribution warehouses often use endless moving flexible belts and/or sequences of rollers, and such conveyor systems typically include tapered rollers to form turns and spiral sections of conveying paths. Another related use for tapered rollers includes web feed rollers used in the production and/or processing of paper or plastic films. Still another is for conveyor drum pulleys used at the ends of belt conveyors; conveyor drum pulleys include outer drums, side panels, and hub assemblies of various constructions that either accept shafts or have shafts welded thereto. The drum face of a pulley can be straight, or can be point crowned, trapezoidally crowned, arc crowned or machined to special shapes; in some cases grooving is included for belt tracking strips.
Support bearing assemblies are typically inserted in the hollow ends of rollers and fitted against the inner surface of the roller to provide for rotatable attachment of the roller to an axle or other support along the opposite sides of the conveyor path. For rollers having small diameter ends, small support bearing assemblies can be fitted directly into the end. While large support bearing assemblies could be fitted into large diameter ends of rollers, such large support bearing assemblies are prohibitively expensive. Therefore, large diameter ends are typically first fitted with a washer before a small support bearing assembly is mounted to the inner surface of the washer. For tapered rollers, the washer is typically selected such that the inner diameter is equal to the inner diameter of the opposite small-diameter roller end.
There are several problems associated with the use of washers to mount small support bearing assemblies to large-diameter rollers. First, the washer provides for connection between the support bearing assembly and roller only along the thin outer and inner diameters of the washer. Such a small connection point is vulnerable to separating or otherwise breaking. Second, the fitting of washers to a roller requires additional manufacturing steps including placing the washer in position and welding it in place. Third, welding washers to rollers adds more inaccuracy to the geometry of the roller since washers must be perfectly dimensioned and arranged within the roller to provide for correct alignment. Typically, the washer must be reamed after being fitted in the roller to ensure proper alignment. Fourth, because welding requires use of unplated rollers, the additional difficulty of plating the finished roller and washer is added when using washers. Fifth, use of washers to provide a mount for support bearing assemblies adds weight to the roller.
To summarize, the prior art use of washers to mount support bearing assemblies to rollers increases supply costs, manufacturing costs, and the time required to manufacture a finished roller having at least one large-diameter end with such a mount. With these things in mind, there is a clear need in the industry for more readily produced rollers with large-diameter ends suitable for use with small support bearing assemblies. In addition, there is a clear need for higher quality rollers with large-diameter ends suitable for industrial use with small support bearing assemblies. More generally, there is a clear need in the field of forming large-diameter metal rollers for improved rollers and methods of manufacturing such rollers.